As described by Matz, Snack Food Technology, conventional corn chip process begins with a corn meal or corn masa. Both white and yellow corn of the dent type are added to a vat containing heated water and a proportionate amount of lime. The mixture is heated to the boiling point, the heat is cut off, and the contents of the vat are allowed to stand undisturbed for 10 to 20 hours. During these heating and steeping steps, the corn hulls are hydrated and partially hydrolyzed. The hulls are softened to a jelly-like consistency and are easily removed later in the process. The starch is also gelatinized. By the end of the steeping period, the corn kernels have absorbed about 50% by weight water. The hulls are removed in a washer by jets of water which also remove any remaining lime. The washed kernels are then transferred to a stone mill where they are ground into dough or masa. The masa is formed (usually by hand) into large cylindrical loaves and then fed into hydraulically powered extrusion presses. The cylindrical chamber of the press contains a closely fitting piston which forces the dough through a die plate having a series of slot-like ports about 1/2 inch (1.27 cm.) wide. A cutting device severs the extruded strands into pieces, usually 1.5 inch (3.81 cm.). Alternatively, the dough can be rolled out into a thin sheet from which shapes can be cut. Dough pieces fall directly into cooking oil held at about 375.degree. F. (190.6.degree. C.). After the moisture content has been reduced to a few percent, the chips are salted, cooled, and packaged.
The conventional process of producing corn chips has the disadvantages of producing chips that are gritty and do not easily melt in the mouth. Corn chips are usually dry and brittle in texture. Corn chips also have a distinctive corn flavor. Potato chips, on the other hand, have a high degree of mouthmelt.
Several patents disclose corn chips made from a combination of corn and potatoes. See for example, U.S. Pat. No. 3,539,356 issued to Benson et al. which describes a process for making snack chips from corn and potatoes in which the starting materials include at least 30% to 70% potatoes. The process comprises mixing the corn and potatoes into a dough, working and shaping the dough into a relatively thin piece having a sheer strength of at least 75 pounds, cutting the dough into chips, and deep-fat frying the chips in oil.
U.S. Pat. No. 3,545,979 issued to Ghafoori discloses a process for producing a snack chip from raw potatoes and whole kernels of corn, wherein the preferred mixture is 60% potatoes and 40% corn. The potatoes are peeled, sectioned, and washed. The corn kernels are steeped in a mild alkaline solution for several hours. Then the sectioned raw potatoes and steeped corn kernels are ground together in a stone grinding mill to produce a dough. The dough is sheeted and cut into chips, and the chips are deep-fried in oil and salted.
U.S. Pat. No. 3,666,511 issued to Williams et al. discloses a snack chip containing 30% to 70% of a cross-linked waxy starch and 30% to 70% of a cross-linked non-waxy starch. Up to 10% of potato starch may be added to this starch mixture.
It is an object of this invention to produce a corn/potato chip with a distinctive mild corn flavor having a texture more like that of potato chips. The corn chip is less gritty than conventional corn chips and it easily melts in the mouth.
This and other objects of this invention will become apparent by the description of the invention below.
All percentages are on a dry weight basis unless otherwise defined.